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CONTENTS Problem Definition

Problem Description

Software requirements

Data protection software

Use case diagram

Data Flow Diagram

Applications

Conclusion

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PROBLEM DEFINITION

Main aim

Develop a cryptosystem for ensuring data security

Used to encrypt or decrypt files , folders or even the drives of a computer

system

Scope of the project is not only to meet the needs of an organisation but also

on individual needs

The proposed system achieves the following goals:

Confidentiality: To protect a user's identity or data from being read.

Data integrity: To protect data from being altered.

Authentication: To assure that data ori inates from a articular art .

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PROBLEM DESCRIPTION

Based on cryptography

Implementing cryptographic techniques such as encryption and

description

Two types of cryptographic schemes

1.Secret key (or symmetric) cryptography

2. Public-key (or asymmetric) cryptography.

Algorithms used are DES,Triple DES,Rijandael algorithms for

message encryption & decryption and RSA for key encryption and

decryption

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WHY CRYPTOSOFT??? Software customizationfacility

Drive Encryptionfacility

Accu

rateoutputis

provided Excellentperformanceforensuringdata security

Helpfultomaintain confidentialdatabases

Simple userinterfaces

Easyimplementation

Low cost hardwarerequirements Userfriendly

Noneedforanymaintanence.

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WHAT IS

CRYPTOGRAPHY??? Cryptography : from the Greek for secret writing

It is the mathematical scrambling of data so that

only someone with the necessary key can unscramble

it.

Secure transmission of private information

Secure storage of sensitive data

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DATA FLOW DIAGRAMS

Level 0 DFD

Crypto

system

PLAIN TEXT CIPHER TEXT

OutputInput

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ENCRYPTION-

TERMINOLOGY

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SYMMETRIC ENCRYPTION &

DECRYPTION

Same algorithm with

same key is used for

encryption &decryption.

Sender & the receiver

must share the

algorithm and the key.

The key must be kept

secret.

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ASYMMETRIC ENCRYPTION AND

DECRYPTION

Sending keys securely

1 algorithm -

encryption &

decryption + a pair

of keys

One of the two keys

must be kept secret.

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COMBINING SYMMETRIC &

ASYMMETRIC ENCRYPTION

Each user should have a pair

of keys (public, private).

Sender encrypt the plaintext

using the receivers public key

and send it to the receiver.

Receiver can decrypt thecipher text with his private

key.

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The proposed software performs the following tasks.

Software Customization

Symmetric Encryption & Decryption

Asymmetric Encryption & Decryption

DATA PROTECTION

SOFTWARE

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Level 1 DFD

( Data Protection Software )

Asymmetric

Decryption

User

Asymmetric

Encryption

Symmetric

Decryption

Symmetric

Encryption

Software

Customizatio

n

CODE NO

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SOFTWARE

CUSTOMIZATION Input a secret code number.

Software performs mathematical calculations and the

result is used to select one of the embeddedcryptographic schemes.

User should use the same customization code for

both encryption & decryption of a document. The sender while sending a cipher text, should

communicate customization code to the receiver.

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Level 1.1 DFD

( Software Customization Module )

User

DES

Algorithm

Triple

DES

Algorithm

Rijndael

Algorithm

RESULT

SELECTION

FLAG

Algorith

m

Selection

Arithmetic

operations

CODE NO

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SYMMETRIC ENCRYPTION

& DECRYPTION The plaintext & the secret key are fed to the algorithm.

The plaintext is divided into blocks of bits.

Each block is again divided and combined with a sub

key and will undergo permutation & substitution

operations to produce the cipher text

The proposed software uses DES , TripleDES &Rijandael algorithms for both encryption & decryption.

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CALCULATION OF F(R,K)

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S box substitution

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DES,TRIPLE DES AND

RIJANDAEL PARAMETERS

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Level 1.2 DFD

( Symmetric Encryption Module )

User

File

Folder

Drive

DES

Encryption

Algorithm

Triple DES

Encryption

Algorithm

PLAIN TEXT

SYMMETRIC

KEY

PLAIN TEXT CIPHER TEXT

Rijandael

Encryption

Algorithm

Encrypteddocuments

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Level 1.3 DFD

( Symmetric Decryption Module )

User

File

Folder

Drive

DES

Decryption

Algorithm

Triple DES

Decryption

Algorithm

Rijandael

Decryption

Algorithm

CIPHER TEXT

SYMMETRIC

KEY

CIPHER TEXT PLAIN TEXTDecrypteddocuments

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ENCRYPTION AND

DECRYPTION This feature is added for transferring the

symmetric key & customization code securely.

The proposed software uses RSA algorithm forencryption & decryption.

RSA algorithm is based on mathematical

techniques rather than on substitution &permutation.

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Level 1.4 DFD

(A

symmetric Encryption Module )

UserRSA Encryption

AlgorithmEncrypted keys

CIPHER TEXT

PUBLICKEY OFCLIENT

SYMMETRICKEY

& CODE NO

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Level 1.5 DFD

(A

symmetric Decryption Module )

User RSA

Decryption

Algorithm

Decrypted keys

SYMMETRICKEY& CODE NO

CIPHER TEXT

PRIVATE KEY OFCLIENT

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USE CASE DIAGRAMS

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Obtain a number

Repeat the entry

Press the customizebutton

SOFTWARE CUSTOMIZATION

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Obtain sourcedrive

Obtain destinationdrive

Obtain Password

Press the Encryptbutton

Obtain source file

Obtain destinationfile

Obtain Password

Press the decryptbutton

DRIVE ENCRYPTION &

FILE DECRYPTION

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Obtain source

drive

Obtain destination

drive

Obtain Password

Press the decryptbutton

Obtain sourcefolder

Obtain destinationfolder

Obtain Password

Press the decryptbutton

DRIVE & FOLDER

DECRYPTION

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Obtain publickey

Obtain private

key

Press generate keybutton

Enter the key

Enter thecode

EnterPassword

Obtain thedestination

folder

Press the encrypt

button

KEY SETTINGS & KEY

ENCRYPTION

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Obtain the sourcefile

Obtain thedestination file

EnterPassword

Press the Decryptbutton

KEY DECRYPTION

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CONCLUSION The primary objective of this system is to protect

confidential documents

Cryptography helps to store confidential data of any size DES, Triple DES and Rijndael algorithms are fast and are

well suited for performing cryptographic transformations

on large streams of data.

The implementation and the design will be presented in the

later phases

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Thank you!!!